The Sessile oak is so-called because its acorns are not held on stalks like those of the familiar English oak. It can be found in woodlands mainly in the north and west of the UK.

Sika deer were introduced to the UK in the 19th century. They are native to eastern Asia.

Sometimes called 'Marsh samphire', wild common glasswort is often gathered and eaten. It grows on saltmarshes and beaches, sometimes forming big, green, fleshy carpets.

As it names suggests, the common crossbill has a large bill that is crossed at the tip - perfect for picking the seeds out of pine cones. Look for it in conifer woodlands, mainly in the north and…

Only a few pairs of snow bunting breed here, so look out for this striking black-and-white bird in winter around Scotland, the North West and the East coast of England.

A dark, stocky warbler, the Cetti's warbler is most likely to be heard, rather than seen - listen out for its bubbling song among willow, marsh and nettles.

The Atlantic salmon spends most of its life at sea, but makes an epic journey back to the river or stream in which it hatched to spawn. Look out for it in freshwater rivers in the north and west…

Look for the delicate, pink flowers of Common bistort in wet meadows, pastures and roadside verges. It is also known as 'Pudding Dock' in North England because it was used to make a…